Variometer



Dem 30.1924. L52L585 T.ca LoLns VARI OMETE R Filed June 9, 1922 ATTORNEYS Dec. 30. 1924. 1,521,585

T. G. LOUIS VARI OMETER Filed June 9, 1922 3 Sheets-Sheet 2 INVENTOR ATToRNYs Dec. 30. 19?..4f 1,521,585

T. G. LOUIS VARIOMETER Filed June 9' 1922 I ilu-Erwin?.-

lNvENToR M 45, i

BY @WE-YM ATTORNEYS Patented Dec. 30, 1924.

UNITED STATES PATENT OFFICE.

TERRENCE G. LOUIS, OF SPRINGFIELD, MASSACHUSETTS, ASSIGNOR OF ONE-THIRD T0 OSCAR B. DEANE, JR., ANI) ONE-THIRD T0 CHARLES W. LOUIS, BOTH OF SPRING- FIELD, MASSACHUSETTS.

VARIOMETER.

Application led June 9, 1922. Serial No. 567,105.

To all wlwm z't may cof/wem: .Be it known that I, TERRENGE G. LOUIS, citizen of the United States, residing at Springfield, in the county of Hampden and State of Massachusetts, have invented new and useful Improvements in Variometers, of which the following is a specification.

The present invention relates to variometers such as are employed for the purpose of varying the inductance in radio circuits. The general object of the invention is to provide a variometer having materially in-4 creased efficiency for a given length of winding.

More specific objects of the invention are to provide a variometer having its parts constructed and arranged to lessen the susceptability of the apparatus to capacity 1nterference from changing atmosp ere conditions or other outside influences; to provide a variometer in which both the stationary and movable windings are thoroughly protected from dust and moisture to provide a variometer having no electrica] connections which are exposed; to provide a variometer having its parts so constructed as to insure a'minimum amount of dielectric losses; and to simplify the construction and reduce the cost of manufacture of variometers, as well 'as to improve the general appearance thereof.

With the above and other objects in view, as will appear from the following description, the invention consists in the features of construction and in the combinations and arrangements of parts hereinafter described and claimed, the advantages of which will be apparent to those skilled in the art.

In the accompanying drawings,-

Fig. l is a plan view of a variometer embodying the present invention in what is now considered to be -its preferred form, the instrument being shown as secured to the vertical panel or side of a cabinet such as is commonly employed to maintain in assembled relation the various elements of a radio receiving set;

Fig. 2 is a view, partially in side elevation, of the variometer shown in Fig. 1, certain portions thereof being broken away and other portions shown in section to more clearly reveal the construction thereof;

Fig. 3 is a sectional view taken along the line 3 3 of Fig. 2, a portion of the rotor being shown in elevation;

Fig. 4 is a sectional view taken along the line 4 4 of Fig. 2;

Fig. 5 is a detail sectional view, on an enlarged scale, of certain of the parts shown in Fig. 4, and

Fig. 6 is a diagrammatic view of the windings and electrical connections.

In the illustrated variometer the inner and outer windings are carried upon relatively movable supporting structures each comprising a thin shell of dielectric material preferably of a character which may be readily stamped or pressed into the desired shape and requisite degree of thinness. As shown in the drawings, the inner windings are supported upon the exterior of a rotatable shell or rotor 1 and the outer windings are secured to the inside surface of a stationary support in form of a casing or housing 2 which surrounds the rotor and completely encloses both the inner and outer windings.

In practice it has been found that celluloid is practicularly adaptable for use in constructing the supporting structures for the windings inasmuch as it combines high dielectric strength with the requisite ability to be pressed into shape and is also capable of being made very thin so that the mass of material employed for supporting purposes may be reduced to a minimum, thereby materially reducing dielectric losses. The use of celluloid is further desirable 4by reason of its resiliency which permits it to withstand rough usage without breaking.

The rotor l consists of a thin globular shell constructed in two similar parts 3 and 4 which overlap somewhat in an axial plane, as indicated at 5 in Fig. 3, and which are securely joined together. The movable windings comprise two coils 7 and 8 which are severally wound upon the parts 5 and 6, respectively. The proximate ends of the coils 7 and 8 are separated by an annular ridge 10 formed by the overlapped portions of the-rotor parts 3 and 4 and are electrically connected as will be later described. The remote ends of the coils 7 and 8 are retained in place upon the rotor shell by project from diametrically opposite points into the rotor shell and are j ournaled in bearings formed in a ring 20 which encircles the rotor in an axial plane and constitutes part of the casing 2. To stiffen the rotor shell and to provide secure anchorage for the trunnions 17 and 18, a girder 22 of wood or other light dielectric material extends diametrically through the interior of the rotor in the plane of the trunnions and is secured in place by means such as the tacks shown at 23 in Fig. 5. The trunnions 17 and 18 may be made of metal and screwthreaded into the ends of the girder. By means of the girder 22, the trunnions aie maintained in alinement and since the latter are made of metal they will not warp or wear excessively, thus insuring the maintenance of the inner and outer windings in accurate concentric relation. The use of the wooden girder further obviates the necessity of extending a metallic pivot rod entirely through the rotor and thus reduces materially the quantity .of metal employed in the construction of the variometer. As shown, the trunnion 17 is journaled in a socket bearing which does not extend through to the outer face of the ring 20. The other trunnion 18 extends through the ring 20 to support an adjusting knob as will hereinafter appear.

The casing 2 comprises two cup-like shells 26 and 27 which arerigidly secured to opposite sides of the ring 2() and which, together with said ring, entirely enclose both the stationary and movable windings. The casing shells 26 and 27 are identical in shape, each being substantially hemi-spherical and each having an outwardly turned annular flange 28 for abutment with the respective face of the ring 20. The flanges 28 are secured to the ring 20 by means of' screws 32, separate screws with short shanks being preferably employed for the two flanges thus avoiding the necessity of passing the screws completely through the ring 20 and consequently further reducing the quantity of metal employed in the construetion of the variometer. At their outer peripheries, the flanges 28 are rolled over, as shown at 29, to overlap somewhat the outer periphery of the ring 20. The stationary Winding, comprises two coils 30 and 31 which are cemented or, otherwise suitably secured to the inside of the shells 26 and 27, respectively, and which are connected with each other and with the coils of the movable winding as will be hereinafter described.

It has been found desirable to make the interior of the casing 2 gas-tight, thus rendering it practical to produce a partial vacuum within said'casing or to fill the easing with a gas other than air, as may be found expedient for the purposes of increasing the sensitiveness and efficiency of the apparatus. To this end the flanges 28 have been cemented to the ring 2O so that hermetically sealed joints are formed between said ring and flanges, and a gland 33 has been provided in the bearin 1n which the trunnion 18 is journaled. Thls gland 33 may comprise a rubber gasket which is compressed within a recess that is counterbored at the inner end vof the bearing for the trunnions 18, shown in 4, said gasket serving to prevent leakage of air or gas through the bearing. Inasmuch as the bearing recess for the other trunnion 17 does not extend through the ring 20 no leakage will occur through this bearing.

The variometer casing 2 is provided with a support 35 which may be used as a bracket by means of which the instrument may be secured to an unright wall'or panel 'such as the panel 36 shown in Figs. 1 and 2, this panel constituting the front wall of a cabinet for a radio receiving set. The support 35, however, is so designed that it may be advantageously utilized as a base whereby the variometer may be conveniently supported upon a table. The bracket or base 35, which is also preferably constructed of Celluloid is made hollow to avoid the presence of any considerable mass of material in proximity to the inductance windings. The bracket 35 is adapted to be secured to the outer periphery of the ring 2O and to this end it is provided with an arcuate web 38 for engagement with said periphery. The web 38 may be secured to the ring 2O by means of screws 39. The web 38 is centrally apertured to permit the passage therethrough of the rotor trunnion 18 when the support 35 is used as a bracket. At the longitudinal edges of the arcuate web 38 are formed ribs 40 (Fig. 1) which slightly overlap the side faces of the ring 2() and assist in maintaining the bracket 35 and the ring 20 in proper' assembled relation, and serving as wel] to improve the general appearance of' the apparatus. The sides of the bracket 35 flare outwardly from the casing 2, as shown` and are provided with outturned flanges l1 which may be bolted or otherwise suitably secured to the panel 36 or other means of support. It will be noticed that the bracket 35 is made of such dimensions that it will space the variometer a substantial distance away from the supporting panel or table to which it may be secured, thus reducingdielectric losses such as would be caused by the proximity of the supporting medium.

When the support 35 is 'used as a base it may be secured to the ring 20 in the position indicated by dotted lines in Fig. 2, thus enabling the rotor trunnions to be maintained horizontal. The support 35 may, however, be secured to the ring in such a position relatively to the trunnion 18 that the latter will be disposed 'at any desired or convenient angle, or so as to permit the mounting of the variometer upon an inclined support. The rotor trunnion 18 lextends through the ring 20 for the purpose of carrying a knob or handle by means of which the rotor may conveniently be turned to vary the inductance of the windings. Preferably the trunnion 18 is made of such length that it may extend through the bracket 35 and panel 36. This construction permits the adjusting knob to be placed at the opposite side of the panel from the variometer itself. When thus mounted upon a panel constituting one side of a cabinet the variometer, although enclosed within the cabinet, may be adjusted from the outside of the cabinet in accordance with the Well-known practice. For the purpose of adjusting the rotor, a combination knob and dial 44 is employed, the same being secured to the free extremity of the trunnion 18. The dial 44 is made from a thin sheet of celluloid and is pressed into the form 'illustrated in Figs. 1 and 2, the center of the dial being provided with a hollow projecting portion 45 ada ted to serve as the adjusting knob. The kno portion 45 is provided with a wooden core or block 46to which it is rigidly secured and the block 46, in turn, is rigldly secured tc the trunnion 18. Suitably arranged graduations may be provided upon the dial 44 to cooperate with a mark upon the panel 36 to indicate the angular adjustment of the rotor. A pin 42 extends cross-wise through the trunnion 18, the opposite ends of said pin projecting as shown in Fig. 2, and being adapted to engage with a stop 43 in the casing 2 to limit the turning of the rotor in both directions.

In accordance with the present invention and for the purpose of further increasing the sensitiveness and efficiency of the variometer the inductance windings and the electrical connections and terminals have been arranged in the novel manner which will now be described.

The remote ends of the two coils which are wound upon opposite sides of the rotational axis ofv the rotor extend inwardly through small apertures in the shell of the rotor and are joined together to form the lead or connection shown at 48 in Fig. 6. This lead 48 extends substantially diametrically through the hollow interior of the rotor shell where it is out of inductive relation with the windings.

The outer` or stationary coils 30 and 31 are connected at their inner or proximate ends with the inner or proximate ends of the movable coils 7 and 8, respectively, by means of flexible connections 50 and 51 commonly termed pigtails which are conveniently turned once or more around the rotor trunnions to permit rotational adjustment of the inner winding relatively to the outer winding. The remote ends of the coils 30 and 31 are connected by short leads 52 and 53 directly with binding posts 54 and 55, respec tively. The connections with the binding posts 54 and 55 are made in the interior of the casing 2, the leads 52 andv 53 curving gradually from the coils to the posts as shown clearly in Fig. 4, thus avoiding'abrupt turns such as tend to occasion current losses. j

With the several coils of the outer and inner windings connected in series in the manner above described, it will be seen that the current will flow from one binding post, through the outer and inner coils at one side of the rotational axis of the rotor and then through the inner and outer coils at the opposite side of said axis. It will further be seen that the inner and outer coils, in each instance, are connected by leads which join together the corresponding ends of the coils, thus avoiding unnecessary loss o current due to the use of long leads or cross-overs which extend across or between the windings. The inner and outer'coils which are connected in the above described manner, are Wound in opposite directions in order to avoid a reversal in the direction of flow of the current therethrough.

For the purpose of effectively insulating the leads 50 and 51 fromthe metallic trunnions about which these leads are turned, insulating spools 57 are mounted upon the trunnions, between the rotor and the ring 20, to receive the turns of the leads. The insulating spools 57 are each formed of celluloid, the spool heads being formed of thin disks 58 (Flg. 5) which are separated from the intermediate portion or sleeve 59 of the spool. The intermediate or sleeve portion 59 of each spool 57 is of sufficiently large outside diameter to hold the disks 58 1n spaced-apart relation but it lits tightly upon the trunnion so as to rotate therewith. The wires leading from the inner coils extend through apertures 60 in the inner disks 58 of each insulating spool and constrain said disks to rotate with the rotor. Preferabl the outer disk 58 is of somewhat greater d1- ameter than the inner disk 58 and said outer disk is adapted to be flexed, as shown in Fig. 5, by contact with the adjacent inner peripheral face of the ring 20, so that its central portion is yieldingly held against llf.)

the sleeve 59 with suflicient tension to frictionally oppose the free turning of the rotor to the extent of electually maintaining the latter in adjusted position.

The binding posts 54 and 55, to which the leads 52 and are secured, are provided at their inner ends with integral heads having convex faces adjoining the threaded shanlts of the posts. Each post is further provided with a nut 62 (Fig. 3) having a concave face of the same radius of curvature as the convex faces of the heads of the bniding posts. rthe Shanks of the binding posts are projected outwardly through apertures in the casing shells. the heads of the posts being located upon the inside of the casing and the nuts G2 are screwed upon the posts with their concave faces directed inwardly toward the casing. Thus when the nuts 62 are tightened the posts will be securely anchored in the casing and the portions of the casing shells intervening between the heads of the posts and the nuts GQ will be cupped outwardly to form depressions in the inner surfaces of the casing shells. This construction enables the heads of the binding posts to be sunk into the casing shells so that they are substantiallyT flush with the inner sul'- face of the casing and will not interfere with the movements of the inner windings as the rotor is adjusted. A second nut 63 is provided on each binding post, bctween'which and the respective nuts 62. the circuit wires may be fastened. To enable screws with ordinary heads to be used for the binding posts the-casing shells 26 and 27 may have recesses suitable for receiving the screw heads formed iu the proper portions of the shells when the latter are pressed into shape.

In many variometers heretofore constructed it has beencustomary to employ a metallic shaft or spindle for rotatably supporting the rotor, and to include this shaft in the circuit by connecting 'the windings thereto. In the present construction. as hereinbefore described, relatively short trunnions are employed to reduce the amount of metal in proximity to the windings and no wires are connected with the trunnions. Furthermore. all connections are made inside of thc shell or housingr 2 and the leads employed are as short as practical.

It has been found in the actual use of the variometers constructed in accordance with the present invention as herein disclosed, that a much higher degree of sensitiveness and efficiency has been attained in proportion to the length of the windings employed, than with any other construction of variometer known to the present inventor. This increased sensitiveness is brought about by the low dielectric losses resulting from the low resistance and the substantially decreased outside capacity interference which characterize the present construction. The

low dielectric losses are duc partially to the character of the dielectric material employed in the construction of the variometer, i. e., its dielectric strength and also its physical qualities which enable it to be pressed very thin so that a minimum bulk of dielectric material may be used. The arrangementy of the various parts of the supporting structures is .such as to tend to reduci` the dielectric losses. The low resistance of the present construction is the result of the elimination of outside wiring, the use of short leads and direct connections, and to the relative locations of the windings. rI`he outside capacity interference is also decreased in the present variometer by the exclusion of dust and moisture from the windings.

The inventor also believes that the increased efliciency of the hereindescribed variometer is partially due to the provision of an air-tight casing enclosing the inner and outer Vwindings irrespective of whether or not the air within the casing is preliminarily rarefied or is replaced either partially or wholly by a .gas of a different character. The enclosing casing is of course designed to protect the windings from dust and moisture, two factors which vary the capacity of the circuits in variometers of ordinary construction. By reason of its tight joints and non-leakable bearings it is obvious that the casing perfectly erforlns these functions and positively e iminates troublesome capacity variation from the above indicated causes.

The invention has been disclosed herein for illustrative purposes in what is now considered its preferred form but the scope of the invention is defined by the appended claims rather than by the foregoing description.

What is claimed is:-

l. In a variometer, an air-tight casing, an inductance coil supported upon the inside surface of said casing, and a second inductance coil within said casing and movable relatively to the first coil for the purpose of varying the inductanee.

2. In a variometer, a rotatable globular frame, an inner winding supported on the exterior of said frame, an outer winding surrounding said inner winding and concentric therewith, and a stationary spherical shell completely enclosing both of said windings and having the outer winding secured to the inner surface thereof.

3. In a variometer, a rotor and a stator, two opposed coils supported upon the rotor at opposite sides of its rotational axis and having their remote extremities connected in series, and two coils supported upon the stator at opposite sides of the rotational axis of the rotor one of the proximate ends of said stator coils being directly connected with the corresponding end of the corresponding coil of the rotor and the other of said proximate ends being directljy connected with the corresponding end ol` the other coil of the rotor, and the directlyr connected coilsl ot the stator and rotor lneing wound in opposite directions.'

4. In a variometer, a stationamP spherical housing of dielectric material comprising a ring member and two similarly torine'd suhstantially heini-spherical shells, said shells having out-turned peripheral flanges and said ring member being` interposed between said flanges and secured thereto, a traine mounted for rotational adjustment within said shell, said trame having a spherical surface concentric with said housingand arranged adjacent 4the inner surface of the latter, an inner coil having its turns wound upon and secured to the outer face of said frame, an outer coil having its turns secured to the inner surface of said shell, and means for rotatably adjusting said frame.

5. In a Variometer, a stationary spherical casing, an outer winding having its turns concentric with said casing and secured to the inner surface thereof, a globular shell mounted for rotational adjustment within said casing and comprising two similar parts overlapped and secured together along the axial plane of said shell, an inner winding comprising coils wound upon the exterior ot said shell at opposite sides of the overlapped portions thereof, and shoulders on said .shell for retaining in position the outermost turns of said coils.

6. Ina variometer, a stationary spherical housing of dielectric material comprising a ring member and two similarly formed substantially hemi-spherical shells, said shells having out-turned peripheral flanges and said ring member being interposed between said flanges and secured thereto. a rotatable frame within said shell, trunnions carried by said shell and journaled in bearings in said ring, an outer coil carried by said housing having its turns concentric therewith and secured to its inner surface, and an inner coil wound upon the exterior of said trame and concentric with the vouter coil.

7. In a variometer, a stationary spherical housing of dielectric material comprising a ring member and two similarly formed substantially hemi-spherical shells, said shells having out-turned peripheral fianges and said ring member being interposed between said flanges and secured the-reto a rotatable frame Within said shell, axially alined tru-.rnions projecting outwardly from said frame and journaled in bearings in said housing, one of said bearings being closed at its outer end, a gland associated with the other of said bearings to seal the joint between sald trunnlon and the adjacent surface, and outer and inner concentrlc windings wound upon inner surface oi" said housing and the outer surface of said traine re- Spectively.

S. In a variomeler, a Stationary Spherical housing of dielectric material, a rotatable hollow shell within said housing, a girclcr ot' dielectric material extending diametrically across the interior ot said shell and rigidly secured at its ends t0 the latter, metallic trunnions secured to opposite ends ot said girder, said trunnions projecting outwardly througl'i said shell and being journaled in bearings in said housing, and outer and inner concentric windings having their turns secured to the inner surface ot said housing and to the outer surface ot said shell. respectively.

9. In a variomcter, a stationary spherical housing, a rotatable shell within said housing, an outer coil having its turns secured to the inner surface ot said housing, an inner coil wound upon the exterior ot said shell. trunnions carried by said shell and journaled in bearings in said housing, said'trunnions and bearings being constructed and arranged to support said shell with the inner and outer coils in concentric relation, a flexible lead connecting said coils in series, said lead being looped around one of said trunnions to permit rotational adjustment of said shell, and an insulating spool mounted upon said trunnion between said housing and said shell to receive said loop and constructed and arranged to frictionally oppose the turning of said shell.

10. In a variometer. a stationary spherical housing, a rotatable shell within said housing, an outer coil having its turns secured to the inner surface of said housing, an inner coil wound upon the exterior of said shell, trunnions carried by said shell and journaled in bearings in said housing, said trunnions and bearings being constructed and arranged to support said shell with the inner and'outer coils in concentric relation` binding posts carried bv said housing, and leads enclosed within said housing for connecting the coils of the inner and outer windings in series and for connecting the terminals of said windings with said binding posts.

11. In a variometer, a spherical housing of coils of the inner' and outer windings in series, said leads being` looped around said trunnions to permit rotational adjustn'ient oi said shell, and spools ot' dielectric material mounted upon said tiunnions between said housing and shell to receive Said loops, each ol' said spools comprising a disk bearing yieldingly against the interior of said housing for :trictionally holding said shell in adjusted position.

l2. In a varionicter. stationary and movable windings connected in series, a housing of thin resilient material enclosing said windings, binding posts carried by said housing to which the terminals of said coils are connected, said posts comprising screws extending through the Wall of said housing,

heads at the incr ends of said screws having convex faces directed toward the adjacent portion of said housing, a nut on said screw outside of said housing having a concave lace corresponding to said convex face and directed toward the Wall of said housing, said concave and convex faces being adapted to cooperate when said nut is tightened to shape a portion of said housing between them to provide a recess in the inner surface ot' the housing to receive said head, and a second nut on said screw between which and the irst nut circuit Wires may be clamped.

In testimony whereof l have affixed my signature.

TERRENCE LOUIS. 

